Regex and nested square brackets to separate subsets

Question

I'm trying to build a quick JavaScript function that will receive a JavaScript object like this:

{
    "sample[one]": "value 1",
    "sample[hard][damn_you[0]]": "this 1",
    "sample[hard][damn_you[1]]": "this 2"
}

And transform it to something like this:

{
    "[sample][one]": "value 1",
    "[sample][hard][damn_you][0]": "this 1",
    "[sample][hard][damn_you][1]": "this 2"
}

Subtle but big difference. I've already worked out the first part, which involves wrapping the first part of the text in a square bracket, but when it comes to take out the nested square brackets and putting them out, I'm at a loss. I've been trying for quite some time without success. Here's what I have so far:

var data = {
        "sample[one]": "value 1",
        "sample[hard][damn_you[0]]": "this 1",
        "sample[hard][damn_you[1]]": "this 2"
    },
    subset = /^([a-z0-9-_]+?)\[/i;

for (var key in data) {
    if (subset.test(key)) {
        data[key.replace(subset,'[$1][')] = data[key];
    } else {
        data[key.replace(/^(.+)$/,'[$1]')] = data[key];
    }
    delete data[key];
}

Which outputs this:

{
    "[sample][one]": "value 1",
    "[sample][hard][damn_you[0]]": "this 1",
    "[sample][hard][damn_you[1]]": "this 2"
}

But am at a loss when it comes to extracting those nested square brackets. Any ideas?

Answer 1

Essentially, you're looking for every consecutive set of characters that are not square brackets. It doesn't matter what order the brackets are in. So you could quite easily do something like this:

key = "["
    +key.replace(/]/g,'[') // replace close brackets with open ones
                           // (to make them the same symbol)
    .replace(/\[+$/,'')    // trim off brackets at the end of the string
    .replace(/\[+/g,"][")  // replace brackets with "][" (separating the words)
    +"]";

So for example sample[hard][damn_you[0]] goes through these steps:

• sample[hard][damn_you[0]]
• sample[hard[[damn_you[0[[
• sample[hard[[damn_you[0
• [sample][hard][damn_you][0]